This invention is generally related to an internal shield for use in optoelectronic ports, and more particularly related to shields that prevent electromagnetic emissions from optical fiber link modules.
Optical fiber is widely used to rapidly and reliably transfer data between computer systems. In general, an optical fiber includes a core region that is coated by an annular clad. The core region has an index of refraction greater than that of the clad, so that light is transmitted through the core by total internal refraction. Optical fibers transmit data from an optoelectronic transducer, such as a laser or Light Emitting Diode (LED), to an optoelectronic receiver that generates electrical information based upon the signal received.
Optical transceivers tend to generate electromagnetic interference (EMI) in the range of about 100 megahertz to 5 gigahertz, and this radiation is most likely to escape from the point at which the fiber is connected to the optoelectronic component. The fibers are typically either threaded onto the optoelectronic components or latched by the use of connectors such MTP or MTO connectors. Because these connectors are typically plastic, however, they are not effective EMI shields. In order to limit EMI, external shielding has therefore been provided in various forms. These shields have an opening that allows the connector to attach to the optoelectronic component. This opening is in effect an electromagnetic hole in the shield that allows EMI energy to escape.
The present invention is an optical fiber link module adapted to receive a fiber optic cable. The optical fiber link module comprises a multiple array lens and a female connector. The female connector is disposed around the multiple array lens, and has an internal cavity. An electromagnetic shield is disposed in the internal cavity, and has a single central aperture sized to permit communication by the multiple array lens through the central aperture.
It is an object of the present invention to provide an optical fiber link module of the type described above having an internal shield that inhibits EMI.
Another object of the present invention is to provide an optical fiber link module of the type described above that permits easy access to the connector and fiber cable by the end user.
Still another object of the present invention is to provide an optical fiber link module of the type described above that is cost effective.
These and other advantages and features, which characterize the invention, are set forth in the claims annexed hereto and forming a further part hereof. However, for a better understanding of the invention, and of the advantages and objectives attained through its use, reference should be made to the drawings, and to the accompanying descriptive matter, in which there is described exemplary embodiments of the invention.